I am so happy that Bactrim is available in India from what PooksiedAnimals said and I am going in the right direction :)

1. For the pain killer-Carprofen, can I give him 0.2 ml twice a day as in the case of Metcam and said by NoCableisSafe?

2. Is it necessary to apply the ointment as I am scared it may not be the right one and he may lick it from the wound?

For the probiotic, I will stick to half a dropping of other guinea pigs poop with water twice a day.

3. Can someone please tell me if I am going right with the Betadine solution?

PooksiedAnimals- He was having soft pellets before the surgery also and it has become softer. He is eating a little everytime I give him food and I make it a point to give him fresh food every one-two hours. I have not been hand feeding him.
4. Should I be concerned about the diarrhoea now?

Antibiotics should be every 12 hours. Poop soup should be 1-2 hours after every dose of antibiotic.

With the pain relief, I'm not sure on the dose, but a good way to administer a pill is to cut it, crush the amount you need (was a quarter a pill for us), mix it in a little baby food and syringe feed it.

He eats food on his own every few hours but he eats less. Should I still handfeed?

For the pain killer, I gave him half a tablet (25mg) dissolved in water and from that solution gave 0.2 ml in the morning. He was sleeping most of the time after that. He ate in between intervals when he woke up though but less.
Should I give him one more dose at night since I have already completed the dosage told by you (a quarter pill)?
I don't want to overdose him with any medicine.

I was told by NoCabbleisSafe to give Metcam twice a day and to give 0.2 ml. I had asked if I can use the same dosage and frequency for Carprofen also.
The full tablet was 50 mg and I gave half, that is 25 mg dissolved in water and gave 0.2 ml of that solution.

Can some one please help with the dosage and frequency of the pain killer?

Also can I give the pain killer directly or maybe mix it with a plurry of vegetables because the baby food here contains lactose?

I dint give Cupid the pain killer last night but now I will give since he has completed 24 hours.
According to what Jessie said, I calculated the dosage of the pain killer. It will be less than a pinch of the whole tablet. Please correct me if I am wrong. Can you please tell me if I can syringe feed this dosage directly in his mouth?

NoCableisSafe- Thank you so much for replying. The problem in India is we don't get good quality pellets and hay. All the pellets contain seeds and are more like a treat. Timothy hay is very difficult to find. Alfalfa hay is available but they are either molded or dirty and since my piggies are above three years, I don't give them alfalfa hay.
I give vegetables and wheat grass, concentrating more on the vegetables.

Cupid had done his surgery three days back and I started with his pain killer the next day, so today was his second day of pain killer.
For how many days should I give him antibiotics, pain killer and probiotics?

Do you have access to meadow hay? I am concerned that your pigs may not be getting enough fiber which is what we really push to feed pigs when they become unwell. This is why Jessie and I keep describing the pellet/museli mash to you instead of just a vegetable puree.

In the diet you're describing of only grass and vegetables you'd want to focus more on grass than vegetables. No pellet diets focus heavily on 24 hour access to hay with lots of vegetables added. I understand you're struggling a bit more over there, I'm just trying to help you understand why I keep nagging at you.

For surgery I only give pain relief for three days post op UNLESS the pig shows signs of still being in pain after the operation. I would only give Cupid one more dose of pain relief and then observe him.

Probiotic is given for as long as you are giving antibiotics and if he has runny poops you can continue this until his poops are back to normal.

Antibiotic depends on why you're using it. Normally for an abscess I've been advised by my vet to give the antibiotic until the wound has closed over (7 days, normally, because for the huge abscesses I've dealt with we keep the wound open until all puss has gone but it doesn't sound like you're having issues with the wound). Longer for an actual infection. 3 days if it's just preventative and everything is going well.

NoCableisSafe- Thank you so much for the detailed information. I can completely understand that all of you want me to give the best to my piggies and I am trying my level best. The problem is that I have to give the best from whatever limited is available in India :(

I will have to find out what is meadow hay called here and if it is available. I had contacted the supplier Pimpinpuji provided and he will get back to me if he can deliver to my home.

I am still giving antibiotics to Cupid inspite of being 9th day of his surgery today because the wound hasn't healed and there is a little swelling. The wound is kept open and I flush it with Betadine solution twice a day.
Should I continue giving him antibiotics?

Took him to the vet today and when he pressed the surrounding area of the wound, Cupid cried with pain but the vet said not to worry as long as the wound is healing.
Should I be concerned?